Preliminary evaluation of the Knox Group in Tennessee for receiving injected wastes

The EPA is authorized under the Safe Drinking Water Act to protect underground sources of drinking water from contamination. However, an aquifer may be exempted from protection and used for injected wastes where the aquifer meets criteria established in the EPA 's Underground Injection Control program. The Knox Group in Middle and West Tennessee occurs primarily in the subsurface, and the top of the Knox Group ranges from about 350 to 3,000 feet below land surface. The upper part of the Knox Group (upper Knox aquifer) is an important source of drinking water in parts of the Central Basin and the Highland Rim provinces. The lower part of the Knox Group is currently being used for injected wastes at New Johnsonville on the western Highland Rim and at Mount Pleasant in the Central Basin. There is no known contamination of the upper Knox aquifer but contamination of the lower part of the Know Group is known at three waste injection well sites. (Lantz-PTT)